gpu: ion: Add trace events for secure cma

Secure CMA allocates and stores memory differently than regular
heaps. This means the regular trace events for tracking allocation
time may not tell the whole story. Add secure CMA specific trace
events for events such as prefetching and shrinking to better collect
data.

Change-Id: I58ce8eb9e94ea380bece6bd75c7ba899a3ebc781
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>